1. Field of the Invention
The present invention relates generally to therapeutic shoes, and more particularly, to low impact exercise shoes designed to stretch and to strengthen foot, leg, and buttocks muscles and tendons. The present invention may be considered in a broader context to be a lower body exercise device, as it is not necessary that the shoes be used in walking or travel. The present shoes have soles with asymmetric curvature in their longitudinal direction (i. e., toe to heel), and are longitudinally reversible to place the greatest curvature beneath either the forward or rearward portion of the foot, as desired.
2. Description of Related Art
Exercise shoes having various shapes and features have been previously constructed for exercise, therapy, and recreation purposes. Some shoes have been developed which have longitudinally convex soles, upon which the wearer may rock forwardly and rearwardly for foot, ankle, and lower leg muscle exercise. These convex sole shoes of the prior art are all unidirectional, i.e., have a specific toe and heel orientation and cannot be reversibly worn. Thus, they provide exercise or flexion of either the anterior or posterior muscle groups, but cannot be reversed to provide muscle exercise for the complementary muscle group.
Accordingly, a need will be seen for an exercise shoe of simple unitary construction that can be used for anterior foot stretches and other exercises and, alternately, reversed for posterior foot flexion exercises. The present rocking shoe invention responds to this need with different embodiments, each having the common feature of a sole with a longitudinally asymmetric convex curvature and longitudinal reversibility, to allow a wearer to position the portion of the sole having the greatest curvature beneath either the forward or the rearward portion of the foot, as desired, to exercise and strengthen corresponding muscle groups.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions in comparison to the present invention, is provided below.
U.S. Pat. No. 1,561,516 issued on Nov. 17, 1925 to Anton Glowa, titled xe2x80x9cFootgear,xe2x80x9d describes devices for wearing over the shoes, for lengthening the stride of the wearer during walking. The devices each include a pair of generally laterally disposed convex arcuate rods therebeneath, upon which the wearer rocks or rolls the foot forwardly while walking. An additional spring loaded plunger is located just behind the heel, which absorbs some of the energy when the heel contacts the underlying surface during walking, and returns that energy to rock the foot forward for the next step. The Glowa appliance does not have a longitudinally asymmetric sole to provide variable radii of rotation during use, as provided by the present rocking shoe invention, and moreover cannot be reversibly worn on the shoe, due to the rearwardly disposed plunger.
U.S. Pat. No. 2,214,052 issued on Sep. 10, 1940 to Harry L. Good, titled xe2x80x9cExercising Boot,xe2x80x9d describes a device for application over an existing shoe, for lower body exercise. The Good boot generally comprises a pair of laterally disposed vertical plates extending beneath a flat sole portion. A compound convex heel plate is provided and the forward ends of the lateral plates have convex curvature, but the central portions of the lower plate edges are straight, rather than providing continuous curvature beneath the foot, as in the present invention. Moreover, the shape of the Good boot and particularly its heel closure and attachment straps, precludes longitudinal reversal of the device. In any event, Good does not disclose any difference between the curvature of the heel and toe portions of his boot, unlike the longitudinally asymmetric and continuous curvature of the present rocking shoe.
U.S. Pat. No. 2,810,213 issued on Oct. 22, 1957 to Jerry J. Jonas, titled xe2x80x9cFootgear,xe2x80x9d describes footwear having an arcuate convex curved sole with a uniform radius of curvature. An alternate embodiment provides two spaced apart and generally vertically disposed plates having arcuate lower edges, rather than a single sole plate. The Jonas footgear differs essentially from the present rocking shoe, in that (1) the sole curvature is of constant and uniform radius and symmetrical from heel to toe, whereas the sole curvature of the present shoe is asymmetric, with a smaller radius at one end than the other; and (2) Jonas provides separate attachment straps configured particularly to fit around the forward portion of the ankle and over the toes, thus precluding fore and aft reversibility, as provided by the present invention. Due to the symmetrical shape of the sole of the Jonas footgear, Jonas has no motivation to provide reversibility, as the same effect would be attained regardless of the longitudinal orientation of the shoe, due to the symmetrical configuration of the sole.
U.S. Pat. No. 3,361,427 issued on Jan. 2, 1968 to Nathan L. Paves, titled xe2x80x9cExercise Rocker,xe2x80x9d describes a single platform for a person to stand upon with both feet, unlike the separate shoes of the present invention. The Paves platform has a generally I-shaped structure therebeneath, with the opposed flanges of the I disposed to the left and right ends and the web of the I extending laterally therebetween. The center portion of the web is parallel to the platform upper surface, with the ends tapering to the narrower flanges. The flanges also taper at their forward and aft ends, in a like manner. No curvature is provided in this supporting structure; all of the defining edges are straight lines. Moreover, the Paves platform cannot be reversed between fore and aft directions, due to the heel stops provided at the rearward edge.
U.S. Pat. No. 3,472,508 issued on Oct. 14, 1969 to Richard E. Baker et al., titled xe2x80x9cExercising Device For Rocking The Foot To Exercise The Lower Leg,xe2x80x9d describes a shoe having a flat sole with a relatively small radius convex curved toe portion. The upper or insole area has a generally sinusoidal curvature, with the forward or toe end being about five times the height of the heel portion, i. e., the toes are elevated considerably above the heel when the Baker et al. shoe is worn. The attachment straps and a lateral heel retaining pin cannot be rearranged to provide for reversal of the Baker et al. shoe, whereas the present rocking shoe is longitudinally reversible to provide exercise for a wider range of muscle groups than the Baker et al. shoe is capable of providing.
U.S. Pat. No. 4,206,558 issued on Jun. 10, 1980 to Vincent J. Bivona, titled xe2x80x9cExercise Shoes For Simulated Jogging,xe2x80x9d describes a shoe having a longitudinally convex curved sole and flat insole. However, the Bivona shoe is longitudinally symmetrical, having the same curvature forwardly and rearwardly of the center, unlike the present rocking shoe invention. The greatest degree of curvature, i. e., smallest radius, is in the center of the sole of the Bivona shoe, whereas it is disposed to one end of the present rocking shoe invention. While Bivona provides a longitudinally symmetrical sole, he positions the attachment strap closer to one end than the other, thus precluding longitudinal reversal of his shoe. The longitudinally symmetrical sole of the Bivona shoe does not provide any motivation for longitudinal reversal, in any event.
U.S. Pat. No. 4,247,996 issued on Feb. 3, 1981 to Pierre A. Grapin et al., titled xe2x80x9cWalking Aid Device,xe2x80x9d describes a shoe intended to increase the length of the stride. The sole comprises a longitudinally arcuately curved plate, with a flat insole surface extending across the inner portion of the arc. The foot attachment straps are asymmetrically arranged, and include a single central heel strap which attaches to a collar which passes around the ankle. Grapin et al. do not disclose any means of rearranging their straps to allow longitudinal reversal of their walking aid, nor do they have any motivation to do so, due to the symmetrical configuration of the arcuate sole. The Grapin et al. device is more closely related to the footgear of the Jonas ""213 U.S. Patent discussed further above, than to the present invention.
U.S. Pat. No. 4,951,938 issued on Aug. 28, 1990 to Christopher J. B. Smith, IV, titled xe2x80x9cExercise Shoe,xe2x80x9d describes a shoe having an longitudinally convex sole plate with a pair of spaced apart plates extending upwardly therefrom. The plates in turn support a pair of longitudinally spaced apart foot supports, with the two foot supports being angled to define a shallow V-shape. The heel support is positioned somewhat higher than the support for the ball of the foot, with the plane of the heel support intersecting the plane of the forward support near the forward end of the forward support. Thus, the entire shoe is longitudinally asymmetric, and cannot be reversed fore and aft to alter the muscle groups exercised while wearing the shoe, as provided by the present rocking shoe invention.
U.S. Pat. No. 5,135,450 issued on Aug. 4, 1992 to Christopher J. B. Smith, IV, titled xe2x80x9cExercise Shoe With Limited Range Of Rocking Motion,xe2x80x9d describes a shoe closely resembling that of the ""938 U.S. patent to the same inventor, described above. The shoe of the ""450 U.S. patent includes a pair of side plates which are removably attached to each side of the shoe structure. The side plates include rollers extending therebetween at each end thereof, with the rearward roller being adjustably installable between a series of holes in the rear portions of the side plates. The rollers pass below the forward and rearward ends of the semicircular sole plate of the shoe, and serve to limit the rocking motion which may be achieved by the Smith, IV shoe. The remainder of the shoe is essentially like that disclosed in the ""938 U.S. patent described above, with the same limitations relating to the lack of fore and aft reversibility.
U.S. Pat. No. 5,713,820 issued on Feb. 3, 1998 to Giuseppe Carbone, titled xe2x80x9cEquipment For Carrying Out Anterior And Posterior Foot And Lower Limbs Flexion Exercises,xe2x80x9d describes various embodiments of a shoe having a longitudinally curved convex sole. The means for securing the shoe to the foot is not reversible, as it includes a strap which wraps about the back of the heel. Carbone does not provide any means for changing the positioning of the straps. Rather, he provides means for interchanging the curved portions beneath the flat insole to which the straps attach, in order to change the curvature as desired.
British Patent Publication No. 1,373,202 published on Nov. 6, 1974 to Alexander M. Panaretos, titled xe2x80x9cA Base For Articles Of Footwear,xe2x80x9d describes a device having a relatively high heel portion and lower forward portion, with the sole having a variable radius arcuate curve thereto from toe to heel. The device utilizes essentially the same principles as the footgear of the Jonas ""213 and Grapin et al. ""996 U.S. patents discussed further above, but utilizes a larger radius curvature across the majority of the sole, relative to the heel and toe curvatures. Panaretos states that the base is to be equipped with an upper portion (shoe, sandal straps, etc.) for securing the device to the foot, but he is silent regarding any means for reversing the device relative to the heel and toe of the wearer.
British Patent Publication No. 1,391,667 published on Apr. 23, 1975 to Hideru Nakamoto, titled xe2x80x9cFootwear For Foot Massage,xe2x80x9d describes a shoe having a single or double wedge shaped lower portion, for either elevating the forward portion of the foot or for rocking about the raised fulcrum in the center of the double wedge embodiment. Each embodiment includes an upper portion which wraps over the forward portion of the foot, with a heel strap extending rearwardly from the upper portion wrap. This foot retaining assembly cannot be reversed relative to the sole portion. Thus, the Nakamoto shoe is restricted to only one longitudinal orientation relative to the wearer""s foot, unlike the longitudinally reversible shoe of the present invention.
Finally, British Patent Publication No. 2,074,009 A published on Oct. 28, 1981 to Lee D. Taicher, titled xe2x80x9cShoe Bottom,xe2x80x9d describes a shoe having a relatively thick sole with a convex longitudinal curvature thereto. The general configuration more closely resembles that of the shoe of the Bivona ""558 U.S. Patent, discussed further above, than the present invention. While the arcuate curvature of the bottom of the sole of the Taicher shoe appears to be longitudinally symmetrical (excepting one embodiment with a small depending heel), the Taicher shoe cannot be reversed longitudinally due to its platform, which closely conforms to the shape of the human foot. In view of the apparent longitudinal symmetrical configuration of the Taicher shoe, there is no motivation to reverse the orientation of his shoe from front to rear in any event.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention is a therapeutic shoe which may be made and used with or without foot straps, and with or without a non-skid surface coating for traction. The shoe has an elongated flat top surface that is preferably rectangular in plan, but may also have an oval or other shape conforming to the foot platform if so desired. The bottom surface of the shoe is longitudinally convex with a continuously changing radius of curvature. The center of mass of the shoe is closer to the second end than to the opposite first end and is located at a distance from the first end approximately three-fifths of the length of the top surface.
The foot straps may be made from plastic, leather, either natural or synthetic fabric, or an elastic material such as a plastic/rubber composite, and linked to the shoe and to each other by snaps, mating hook and loop material, etc. so that they are easily removable from the shoe. The shoe may be reversed 180xc2x0 on either foot. The alternate orientation enables the user to stretch and strengthen different muscles of the leg. In one orientation, the heel of the foot is just aft of the center of mass of the shoe. In this manner, the user can lift his or her toes upward and rock his or her heel backward from the center of mass, which serves as a fulcrum, to contract and strengthen the anterior leg muscles. In another orientation, the shoe is turned 180xc2x0 and the straps (if used) repositioned as required such that the ball of the foot is generally over the center of mass. In this manner, the user can press his or her toes downwardly and rock the shoe forward past the center of mass near the fulcrum, to contract and strengthen the posterior leg muscles, while stretching the anterior leg muscles.
The exercise movements with the present shoe are facilitated by the fact that the bottom surface has at least three sections, each having a different average degree of curvature. The three sections include a central section having a medium degree of curvature to allow a complete rocking motion for the purpose of stretching and strengthening the leg muscle without so great a curvature such that the shoe would be significantly unstable, and a strapless shoe would thus not be possible. A first end portion has a relatively low average degree of curvature, and extends from about the first end to the central section. (The extreme end may be somewhat blunted, for greater strength.) The relatively long radius curvature is important so that the shoe can rest in a stable, substantially horizontal position when a person mounts the shoe, with or without the straps. This shallow first curvature is also critical in that it provides a gradual transition from the sharper central curvature, and thus provides a smooth xe2x80x9cridexe2x80x9d for the user. A second section has a relatively high degree of curvature, and extends from the central portion to the second end of the shoe.
Accordingly, it is a principal object of the invention to provide a rocking shoe of unitary construction which may be used to stretch and to strengthen the muscles and tendons of the foot, ankle, and legs.
It is a further object of the invention to provide a rocking shoe with a first end portion and an opposite second end portion, each having a bottom surface with different degree of curvature which enables the user to work different muscle ranges.
It is another object of the invention to provide a rocking shoe which has a flat upper surface such that the shoe may be reversed longitudinally relative to the foot of the wearer to provide two alternate ranges of flexion for the foot.
An additional object of the invention is to provide a rocking shoe in which foot retaining straps, if provided, may be reversed relative to the first and second ends of the shoe for reversal of the orientation of the shoe on the wearer""s foot as desired.
Still another object of the invention is to provide a rocking shoe in which at least one embodiment does not require straps or other means to secure the shoe to the foot of the user, for stationary exercises.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.